A termite insecticide is applied or sprayed onto a base or under floor in constructing an object building and should thereafter have residual effectiveness for a long time in soil etc., and thus requires periodical monitoring of concentration. With respect to the form of an active ingredient of a termite insecticide, there are cases where the active ingredient is contained in an emulsion or capsule preparations such as microcapsules.
Conventionally, the concentration of a residual active ingredient in a termite insecticide has been analyzed by extracting a termite insecticide component from e.g. soil as the object, purifying the component and measuring it by gas chromatography (GC). That is, usually the sample is extracted with an organic solvent, purified through a plurality of columns such as porous diatomaceous earth column, florisil column, silica gel column, C18 column, and florisil column in order and then measured by GC. Such measurement method is satisfactory in respect of accuracy and sensitivity, but requires expensive facilities and sophisticated techniques and is thus not suitable for outside measurement.
Immunoassay methods, on the other hand, comprise measuring an antigen by utilizing the specific reactivity of an antibody against the antigen, and is thus excellent in measurement accuracy without requiring a complicated purification step or expensive facilities such as in the above-mentioned GC, thus making the measurement methods rapid, easy and economical. Conventionally, immunoassay methods play an important role in analyzing clinical states of patients in the field of clinical diagnosis, and in recent years, application thereof to measurement of environmentally burdening chemical substances is advancing. For some termite insecticides, a method of immunologically measuring an active ingredient of a termite insecticide, which comprises using a monoclonal antibody produced with the use of, as immunogen, a conjugate of a derivative of the active ingredient to which a protein was bound thereto, has been developed (for example, Japanese Patent Application Laid-Open No. 2000-191698).
The substance used as an active ingredient of a termite insecticide includes organophosphorus-based insecticides such as chlorpolis, fenitrothion and pyridaphenthion, pyrethroid-based permethrin and tralomethrin, creosote oil that is a mixture of cresol and naphthalene, phenylpyrazol-based fipronil, and neonicotinoid-based imidacloprid.    Patent Document 1: Japanese Patent Application Laid-Open No. 2000-191698